Field: This invention relates to switches for electrically powered machines and more particularly to safety switches for use with machines such as electrically operated exercise machines.
State of the Art: Various types of electrically powered machines including, specifically, exercise equipment such as treadmills, employ an "on" and "off" switch in order to cause the machine to be turned on or energized and subsequently turned off or de-energized. A wide variety of switches may be used, including push button switches, toggle switches and sliding switches. Typical switches as noted require a positive action on the part of the user to place the switch in the "on" position and another positive action to place it in the "off" position. Because of the physical arrangement of some of the switches, it may be accidentally moved from an "off" condition to an "on" condition. That is, someone could bump the switch or accidentally depress it to cause a machine to be energized. For some machines, accidental energization may be dangerous and may even cause an accident and injury.
U.S. Pat. No. 4,771,148 (Bersonnet) discloses an exercise machine switch in which the user must perform two actions to cause the switch to be placed in an "on" condition, and one action to cause the switch to be placed in an "off" condition. Therefore, accidental energization or activation by placing the switch in the "on" condition is minimized. Yet rapid de-energization may be effected because only one action is involved.
Switches such as those disclosed in U.S. Pat. No. 4,771,148 have not received widespread acceptance for use on exercise machines because the exercise machines involved appear to have evolved to machines having a control console containing various operating switches, dials and other information for the user. A suitable switch which cannot be accidentally activated without a positive action on the part of the user is desirable for use with powered machines and more particularly, powered exercise machines with a control console arrangement.